Transmission Line Parameters Research Articles

An enhanced distance protection algorithm based on characteristics-travelling waves measured from the current for HVDC Lines

It is a vital challenge to perfectly and reliably position high impedance faults and remote end faults in high-voltage direct current (HVDC) transmission lines. Also, distance protection systems are very vulnerable to maloperation under power swing situations and noise interference. These challenges are essential for system stability. This paper succeeded in these challenges with high accuracy, reliability, and stability and without delay in protection startup for single pole-to-ground faults and pole-to-pole faults during ultra-high-speed. The paper presents new employment for the 2nd order of the sequential overlapping difference (SOD) tool to capture transient component characteristics of both terminals of the DC-TL, calculate the fault distance, and identify the faulted pole. Also, it presents novel employment of external disturbances to estimate the fault location. This employment protects the proposed technique from the errors resulting from the mistakes in knowing the transmission line parameters data. The paper studies a bipolar-HVDC-TL system established in (ATP/EMTP). Besides, the proposed algorithm is valid for both single-pole and two-pole operation modes. Also, it suggested an amplification process to magnify the stability margin between normal and abnormal operations. And, it verifies the decision by employing more than information. In addition, the distributed capacitance does not affect it.

Application of Catenary Equation in Calculation of Transmission Line Parameters

Application of Catenary Equation in Calculation of Transmission Line Parameters

Influence of Temperature and Transmitted Power on Losses in Particular Transmission System

Innovations and trends has been significantly increased during modern theory and practical realizations in the field of energetic. In the Czech Republic, the research of predictions of technical losses on the transmission system can be considered as novel and important topic. Using software possibilities can be appropriately utilized in the frame of estimations of the technical losses. While they cannot be eliminated, they may be minimized. Losses can be measured or calculated using transmission-line parameters. This causality is considered in the form of the presented and proposed mathematical equations including real measured data of the atmospheric temperatures achieved on the substations selected in the Moravian-Silesian region. In this contribution, results of proposed calculations of technical losses based only on line parameters considering the ambient temperature are being compared in relation to a particular transmission system using prediction software. Particularly, technical losses caused by a configuration change of a selected part of a transmission system are considered related to the operation of Dlouhe Strane pumped storage hydro power plant. As can be conclude, after the resulted comparisons using by the proposed mathematical models in software and the obtained real measured data, general minimization of the losses is necessary to create the most accurate models of the states that might occur in the future and to propose required modifications of the given part of the transmission system. Future bounded research can be focused on the sensors situated on the transmission lines instead of the substations.

Optimally detecting and classifying the transmission line fault in power system using hybrid technique

In this paper, a hybrid system is proposed to predict and classifies the power system transmission line faults. The proposed technique is the consolidation of both the truncated singular value decomposition (TSVD) and Human urbanization algorithm (HUA) based Recurrent Perceptron Neural Network (RPNN), and hence it is named as TSVD-HUARPNN technique. TSVD is matrix decomposition, this technique qualify the outcome it as fast or not. In the proposed work, the qualification of the results from the TSVD is improved by a lemma theorem; it is a proven proposition which is used to obtain a larger and optimal result. For that reason, it is also known as a ”helping theorem” or an ”auxiliary theorem”. Here, it has two modules for power system fault analysis: (i) fault detection, (ii) fault classification. The first process of the proposed system is the generation of the dataset of normal and abnormal conditions of transmission line parameters of power system using TSVD. The extracted dataset is assessed by HUA-based RPNN system to classify the fault analysis that occurs in transmission system. The TSVD-HUARPNN system is used to predict and classify the fault present in the transmission line. The proposed TSVD-HUARPNN system ensures the system with less complexity for the detection and classification of the fault, therefore the accuracy of the system is increased. By then, the proposed model is activated in MATLAB/Simulink, its performance is evaluated with the existing models. The performance with noise at 20 dB of the proposed technique is 99.77%.

Model parameter identification for scaled-down analogous HVDC transmission lines using broad spectral response analysis

Traditional analogous π-shape transmission line models are mainly designed based on the amplitude and phase response characteristics of the distributed-parameter transmission lines at the power frequency. It cannot be directly used to build analogous high-voltage direct current (HVDC) transmission line models because the signals in a wide frequency band from 0 Hz to 10 kHz are used to protect HVDC transmission lines instead of power frequency components. In this paper, a novel model parameter identification method for scaled-down analogous HVDC transmission lines is proposed based on broad spectral response analysis. The broad spectral responses of distributed parameter-based and π-shape lumped parameter-based models are analyzed and compared with each other first. And then frequency-dependent per-unit parameters of HVDC transmission lines are obtained and used to form a modified π-shape HVDC transmission line model with the same zero- and positive-sequence​ impedance as those of distributed parameter lines. The element parameters of the π-shape circuit model are identified optimally based on the weighted sum of the results at selected several frequencies in the broadband from 0 hertz to thousands of hertz. The simulation results show that the amplitude and polarity of the dc voltage and current in our scaled-down analogous lines are close to distributed parameter-based HVDC transmission lines once a fault occurred on the lines.

Devising a method for reducing active power corona losses based on changing the structural parameters of a power transmission line

This paper reports a study into the influence of the main design parameters of power transmission lines on energy losses associated with the corona discharge; a method has been devised to reduce them. The structure of the split-phase wire, the distance to the ground, and between the centers of the phases of the line are determined at the design stage. Based on these structural parameters, the value of specific energy losses associated with the corona discharge is calculated. Studying the impact exerted on the amount of losses by each structural parameter makes it possible at the design stage to determine the structure of a power transmission line (PTL) with low energy losses. Reducing energy loss when transporting it along the line is one of the most important issues in the strategy for the development of the energy industry at the stage of the "green transition". It has been established that most structural parameters have a weak effect on the values of corona losses, and, if there is a significant impact, the implementation of such solutions leads to a large increase in the cost of constructing an overhead transmission line. Based on the analysis of the results of calculations of corona losses in power transmission lines, it was determined that the corona losses in the middle phase of the transmission line are much greater than in the extreme phases. That has made it possible to devise a method for reducing power corona losses associated with the alignment of the capacities of all phases of PTL. This effect is achieved by calculating, based on the developed method, the splitting step of the middle phase of PTL. The calculation of the splitting step is based on the preliminary determination of the capacity of the extreme phases and the substitution of calculated values in the resulting expression for the splitting step. The possibility of such a reduction in corona losses should significantly increase the energy efficiency of AC power transmission lines, especially in areas with large periods of different weather that provoke the occurrence of a corona discharge on the wires of their phases. This circumstance causes an increase in this type of power loss.

New method of measuring the zero-sequence distributed parameters of non-full-line parallel four-circuit transmission lines

This paper proposes a measurement method of zero-sequence distributed parameters for non-full-line parallel four-circuit transmission lines. Considering the distribution effect and different parameters of each part of the transmission lines, the distributed parameter models are used for modelling. Deriving the line models’ transmission equations by applying the Laplace transform to the Telegrapher’s Equations. Synchronously measuring voltages and currents at two ends of the transmission lines under four measurement modes, and substituting the zero-sequence phasors into the total transmission equations to calculate the elements of the transmission matrix. According to the elements of the transmission matrix and intermediate variables, 24 zero-sequence distributed parameters of the whole transmission lines can be calculated, including 6 zero-sequence parameters of the double-circuit part and 18 zero-sequence parameters of the four-circuit part. The simulation results by using PSCAD/EMTDC show that compared with the traditional method, the proposed method overcomes the influence of distribution effect and considers the parameters are different due to the different electromagnetic coupling relationships, and the measurement accuracy is greatly improved. The sensitivity analysis of the line parameters shows that the proposed method can be applied to non-full-line parallel four-circuit transmission lines under arbitrary mixed voltage conditions. The simulation analysis under noise environment and measurement errors shows that the proposed method has strong anti-noise and anti-measurement-errors ability.

Measurement and modeling of effective cable parameters of unshielded conductors

PurposeCables are ubiquitous in electronic-based systems. Electromagnetic emission of cables and crosstalk between wires is an important issue in electromagnetic compatibility and is to be minimized in the design phase. To facilitate the design, models of different complexity and accuracy, for instance, circuit models or finite element (FE) simulations, are used. The purpose of this study is to compare transmission line parameters obtained by measurements and simulations.Design/methodology/approachTransmission line parameters were determined by means of measurements in the frequency and time domain and by FE simulations in the frequency domain and compared. Finally, a Spice simulation with lumped elements was performed.FindingsThe determination of the effective permittivity of insulated wires seems to be a key issue in comparing measurements and simulations.Originality/valueA space decomposition technique for a guided wave on an infinite configuration with constant cross-section has been introduced, where an analytic representation in the direction of propagation is used, and the transversal fields are approximated by FEs.

A new four‐step method to identify the parameters of transmission line based on SCADA data

Accurate parameters of transmission line (ParTL) are the basis of power system analysis. For high-voltage transmission line (TL), remote terminal units (RTUs) are widely installed to provide supervisory control and data acquisition (SCADA) measurements. Based on multiple snapshots of SCADA data at both ends of the TL, a four-step method to identify ParTL is proposed in this paper. In detail, based on the π-model of TL, the relationship between voltage phase angle difference (VPADs) and parameter identification is presented. And then, the general estimation formulation for VPADs is established. Furthermore, four steps to simplify and solve the formulation are detailed, that is, firstly after the approximated relationship between VPADs and reactance are derived, the estimation of VPADs at multiple snapshots is converted into the optimal problem with reactance of TL, just one variable, and the VPADs are estimated roughly; secondly based on the median estimation, the ParTL are identified roughly; thirdly, combined with Taylor series expansions and the alternating current power flow model, the VPADs are estimated accurately; fourthly, the ParTL are identified accurately. Finally, the results with simulated and field data verify the effectiveness and practicality of the proposed method.

Enhancing the resiliency of transmission lines using extreme gradient boosting against faults

The study presented in the paper aims to reduce the relaying time associated with detection and classification of fault along with accurate fault location estimation with the help of Teager Kaiser energy operator (TKEO) and extreme gradient boost (XGBoost) algorithm. The complete analysis has been conducted on IEEE 14 Bus transmission network. Four XGBoost modules corresponding to each phase have been developed for fault detection, classification, and similarly four regression modules are developed for fault location estimation depending on the type of fault. The proposed methodology is able to precisely determine the fault, locate it and also recognize the faulty phase(s). Special attention has been paid in determining the high impedance fault (HIF) apart from usual low impedance faults (LIF) while varying the fault parameters such as evolving nature of faults, fault inception angle, power flow angle and change in transmission line parameters etc. Voltage and current measurements recorded at the relay location are utilized. Moreover, the proposed XGBoost algorithm-based approach is able to detect and classify faults in around 1–2 ms time. The absolute error in fault location is around 0–2 km in most of the scenarios. A comparative study clearly states the merits of the proposed scheme.

Systematization and monitoring of quality parameters of overhead power transmission lines functioning

On the basis of quality control methods, the analysis of the causes of technological disturbances (accidents) on overhead power lines was carried out. In particular, the Ishikawa diagram, the Pareto diagram were developed, which made it possible to systematize the main causes of technological violations. The necessity of monitoring the indicators of the reliability of the functioning of overhead power transmission lines by means of information-measuring systems has been substantiated. The structure of an information-measuring system for monitoring parameters that have a negative impact on the functioning quality of overhead power transmission lines is proposed. The proposed system is aimed at ensuring the reliability of the electrical networks operation and improving the quality indicators of services provided to consumers for the transmission of electrical energy.

Evaluation of High-Speed Link Parameters for Highly Reliable Reconfigurable Systems Based on S-Parameters and BER

Purpose of research. is to improve signal transmission parameters in high-speed signal transmission lines, including between programmable logic integrated circuits (PLIC). This improvement in signal transmission parameters is necessary to increase throughput of modern highly reliable reconfigurable systems to ensure data transfer rate of up to tens of Gbit/s. It can be done considering the influence of electrical and structural parameters of multi-layer printed circuit boards (MPCB) on them. It is possible to provide such high data rates by using a wider frequency band of transmitted signals. One of the existing approaches to this problem is to increase "physical" frequency of transmitted information signals to 25-300 GHz, which is sufficient to achieve desired rates.Methods. A method for estimating quality of high-speed signal transmission lines based on the definition of standardized methods for analyzing signal transmission parameters, such as JCOM, S-parameters and BER is proposed in the article. This method allows evaluating high-speed communication lines. Thus, the Channel Operating Margin (COM)/JCOM parameter can be used to estimate the quality of a digital communication channel - a standardized method for determining the overall channel quality indicator. Known methods are used to estimate such signal transmission parameters as S11 reflection coefficient and S21 attenuation coefficient (S-Parameters). These methods are used to estimate attenuation and loss of the information signal in the path, when copies of the signal reflected from inhomogeneities affect the original and lead to its distortion. Simulation of such parameter as Bit Error Rate (BER) is carried out according to G.821/G.826/M2100 rationing and quality control methodology.Results. The main metrics were selected to evaluate the quality of high-speed signal transmission lines. It is based on the evaluation of such signal transmission parameters as Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER). Numerical evaluations of signal transmission parameters were obtained and their effect on the design parameters of high-speed signal transmission lines was estimated. It is recommended to use at least 1 transition hole between screening polygons in GND separation layers every 0.5 cm or 0.25 cm2 of WFP area. It is for a data rate of less than 25 Gbit/s, It is recommended to use at least 2 transition holes between screening polygons in GND separation layers every 0.5 cm or 0.25 cm² of PV area, if high-speed signal transmission line passes at a distance of closer than 2.5 cm from the power supply circuits in a projection on the layer where the power supply circuits are located.Conclusion. A method for calculating signal transmission parameters on high-speed signaling lines based on the calculation of Channel Operating Margin (COM), S-parameters and Bit Error Rate (BER) parameters is introduced. As part of introduced method, an analysis of signal transmission parameters was carried out. This analysis shows that when the "reference" values of electrical parameters of the line are met, the transfer holes contribute most to the signal distortion; then the layers in which the signal line is located, the number of screening polygons between the signal layers and the layers; in which the power supply circuits, the design parameters of the transition holes, as well as the length and number of segments of the high-speed line pass. Numerical evaluations of minimum number of transition holes and their diameter, the length of segments of differential pairs are given. These results can be used in pre-layout analysis step of high-speed signal transmission lines for computational modules of highly reliable reconfigurable systems.

Estimation of the Frequency-Dependent Parameters of Transmission Lines by Using Synchronized Measurements

Transmission line parameters are usually calculated based on technical and environmental approximations, e.g. line height, cable conductivity, etc. These characteristics vary depending on the environment and technical issues, meaning that the transmission line should be considered as a dynamic system with time-varying parameters. Estimation methods are a useful way to determine line parameters taken into account such characteristics. Most methods estimate these parameters at 50 ~ 60 Hz, useful for steady state analysis. However, for transient state or harmonic distortion analyses, a frequency range should be estimated, which varies according to the phenomenon to be investigated. In this matter, considering the gap existent of studies to estimate frequency-dependent parameters, we propose an efficacious and simplified method based on the two-port line representation and the well-known least squares method to estimate these parameters of a transmission line with 400 km length, considering a minimum number of synchronized measurements from 1 Hz up to 250 Hz.

Transmission Line Parameter Estimation Under Non-Gaussian Measurement Noise

Accurate knowledge of transmission line parameters is essential for a variety of power system monitoring, protection, and control applications. The use of phasor measurement unit (PMU) data for transmission line parameter estimation (TLPE) is well-documented. However, existing literature on PMU-based TLPE implicitly assumes the measurement noise to be Gaussian. Recently, it has been shown that the noise in PMU measurements (especially in the current phasors) is better represented by Gaussian mixture models (GMMs), i.e., the noises are non-Gaussian. We present a novel approach for TLPE that can handle non-Gaussian noise in the PMU measurements. The measurement noise is expressed as a GMM, whose components are identified using the expectation-maximization (EM) algorithm. Subsequently, noise and parameter estimation is carried out by solving a maximum likelihood estimation problem iteratively until convergence. The superior performance of the proposed approach over traditional approaches such as least squares and total least squares as well as the more recently proposed minimum total error entropy approach is demonstrated by performing simulations using the IEEE 118-bus system as well as proprietary PMU data obtained from a U.S. power utility.

Time-domain Analysis of Traveling Wave Switches based on Time-variant Transmission Line Model

Background and Objectives: Switches play an important role in controlling the signal flow in telecommunication systems. The traveling wave switch structure is introduced based on active transmission lines. By applying the gate voltage (Vg), the transfer of signal through the drain transmission line is controlled. By increasing operating frequency, lumped model is unreliable and semi and fully distributed modeling should be applied for the analysis of these elements. Methods: Traveling wave switches can be analyzed based on the lossy transmission line model, in linear and non-linear modes in the time and frequency domains. The study of transient behavior and time domain response of switch is very important. Switching and transient from on to off state and vice versa affect the performance of telecommunication systems.In the proposed method, the switch is modeled as the lossy transmission line that the primary elements of this model change with time based on the control voltage applied to the gate and are considered as variable with time. The structure is discretized in the space and time domains with ∆z and ∆t steps. The Finite-difference time-domain (FDTD) method is utilized to study the transient response of switches. By using the leap-frog algorithm, the new voltages and currents of the transmission line are calculated based on the values of adjacent spatial and temporal steps.Results: The transient response of the switch is analyzed in transition from off to on states and vice versa, for the 800µm switch at 60GHz, based on the parameters of the passive transmission line and nonlinear Curtice2 FET model.Conclusion: For transient analysis of the structure, the time-variant lossy transmission line model was used that its elements changed based on the applied control voltage. The results of FDTD method were investigated with the transient analysis of commercial software that show good agreement with each other and validated the proposed method.

PMU-Based Estimation of Systematic Measurement Errors, Line Parameters, and Tap Changer Ratios in Three-Phase Power Systems

The availability of accurate data is fundamental for several monitoring and control applications of modern power grids. Nevertheless, the knowledge of critical data, such as transmission line and transformer parameters, is often affected by uncertainty. This can lead to important problems in the correct management of the power systems. In spite of a monitoring infrastructure that is being renewed due to new generation devices providing synchronized measurements, the actual values of line parameters and tap changer ratios are still affected by uncertainty sources that need to be properly considered. The behavior of all the elements involved in the measurement chain must be duly modeled. This article proposes an improved method to carry out the simultaneous estimation of line parameters, tap changer ratios, and systematic measurement errors for a three-phase power system. The proposed method is based on the suitable modeling of the measurement chain and three-phase constraint equations (voltage drop and current balance) of all the components involved. Its effectiveness is confirmed by tests performed on an IEEE 14-bus test system reproduced as a three-phase system under different operative conditions.

Influence of transmission line parameters on the degree of matching of the generator with the SIS-mixer in the frequency range 200-700 GHz

This work is aimed at the development, research and optimization of superconducting integrated circuits designed to match the impedances of a long Josephson junction generator, the so-called flux generator (FFO) and a superconductor--insulator--superconductor (SIS) detector in the sub-terahertz frequency range. Numerical calculations of integrated circuits designed to optimize the parameters of transmission lines are presented. The main parameters of the lines and their influence on signal propagation are determined. The results of optimization of integrated matching circuits in the range of 450-700 GHz are demonstrated. Keywords: integrated matching circuits, Josephson junctions, sub-terahertz generator.

Impedance Parameters Estimation of Transmission Lines by an Extended Kalman Filter-Based Algorithm

The accurate knowledge of the electrical parameters of transmission lines is an important issue for, e.g., fault detection and location, stability analysis. In this sense, the reliability in which such parameters are determined shows to be crucial to the entire system operation. In this article, we propose the estimation of both phasors and parameters through a nonlinear approach by using the Kronecker product, in order to determine the Jacobian terms, and thereafter the extended Kalman filter (EKF). The parameters estimation is carried out recursively in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$d$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula> domain, based on the phasor rotation dynamics for a given frequency. The results presented a reliable and accurate estimation compared to another approach based on Kalman Filtering method. The nonlinear approach, applying the Kronecker product and EKF, represents the original contribution of the proposed estimation method. Besides, this method is applicable to large systems, since the transmission line have to be modeled by the equivalent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula> model using the hyperbolic corrections.

Crosstalk prediction and statistical properties of transmission line

In this paper, for the crosstalk error problem of multi-core stranded wires caused by non-uniform pitch, the Monte Carlo method is used to establish the probability distribution model of non-uniform pitch of stranded wires. For stranded wire crosstalk prediction, a transmission line pa-rameter prediction model is constructed using the BSO-BP neural network algorithm, and the effec-tiveness of the algorithm in this paper is verified by simulation. The final calculation gives the statis-tical characteristics of crosstalk on multicore stranded wires.

Способ определения комплексного значения совокупных потерь полной мощности в системе электроснабжения

Предложен способ расчета совокупных потерь в оборудовании системы электроснабжения, используемого для транспортировки электрической энергии, где учтены в целом совокупности элементов системы электроснабжения и нагрузки, связанные общим режимом работы, в отличие от известных способов, в которых потери рассчитываются отдельно по составляющим и по виду оборудования. В основу способа положена схема замещения системы электроснабжения, в которой для силового трехфазного двухобмоточного трансформатора использована приведенная симметричная Т-образная схема замещения одной фазы. Аналитически доказано, что рассмотрение вопросов, связанных с расчетом потерь в системе электроснабжения порознь в линии электропередачи и силовом двухобмоточном трансформаторе без учета их взаимного влияния друг на друга, приводит к неточности расчета. Выполнена оценка погрешности расчетов потерь и потребления полной мощности по предлагаемому способу в сравнении с математической моделью. Математическая модель разработана в программном комплексе Multisim. В качестве примера для выполнения расчетов принята система электроснабжения, состоящая из источника с номинальным напряжением 10 кВ + 10 %, линии электропередачи, выполненной трехжильным кабелем, силового трехфазного двухобмоточного трансформатора марки ТМГ11 номинальной мощностью 250 кВА и нагрузки. Расчетные значения, при использовании разработанного способа, практически совпадают с данными, полученными по итогам работы математической модели. Выполнен расчет суммарных потерь активной мощности, в принятой для математической модели системе электроснабжения, при расчете отдельно нагрузочных потерь в линии электропередачи и условно-постоянных и нагрузочных потерь в силовом трансформаторе. Относительная погрешность результатов расчета суммарных потерь активной мощности в этом случае составила 12,6 %. Доказано, что использование разработанного метода позволяет повысить точность расчета совокупных потерь и делает возможным выполнение дальнейших исследований, направленных на оценку влияния параметров питающей линии электропередачи, нагрузки и величины питающего напряжения сети на совокупные потери в оборудовании системы электроснабжения, используемого для транспортировки электрической энергии.